HELP: WhazIt? TR switch?

[Ian Webb]

Along with some other equipment I acquired what I believe to be a
1950s, early 1960s TR switch.

I recognize the power supply it's attached to as a modified AMECO
unit.  I can't remember the details of the unit in the foreground of
this picture which I believe is a TR switch.  I also seem to remember
it being late 1950s to early 1960s vintage.

Take a look at:
http://www.geocities.com/k6sde/TR_Switch/TR_switch.jpg

Anybody with a better memory than mine?

Who made it?  (Johnson???)
What does it do?  ("isolate" the receiver from the antenna??? or??)
How does it fasten into the antenna system?

I probably won't ever use it but would like to know more about it
before I make that decision.  If I know the years when it was sold I
can go to the library and try to find an ad or article in and old QST
about it.

Ian, K6SDE
k6sde at my-deja.com